Long title moves on save

[jakirkham]

Sadly I have some notebooks with long titles to keep track of what data they are working on and what I am trying to do with them. If the filename is very long, then I sometimes see this minor UI annoyance on saves where the title moves. Depending on the title length, this behavior can become time dependent on the time of the last save. One thought might be to move the location of language icon so the title can't run into its space. Though there are plenty of other reasonable ideas. Sorry to trouble with such a minor issue.

[JamiesHQ]

cc: @gnestor

[gnestor]

I just submitted a PR that should fix this: #2448

It enforces a max-width: 100% and uses display: flex on the save_widget container and uses a text-overflow: ellipsis to clip the title if it overflows.